I have been using the free version of xplit for a while when I stream. What do others use? I just came across this the free streaming software and it is not nearly as resource intensive as Xsplit http://obsproject.com/index I know some people use ffsplit http://www.ffsplit.com/ There is also this that people use http://dxtory.com/v2-home-en.html
Best combo I have found is avermedia live gamer hd capture card along with xsplit can stream 720p with only 10 percent fram loss. I know its 200 bones but well worth it hell I can record 1920 1080p with no fram loss.
obs dropped my streamed fps to around 15-20 during LoL with every change to settings I could possibly make. Xsplit streams flawlessly on the same settings without a single hiccup. OBS will need a few tweaks I think to handle multi-core proccessors well.